I got the Mirena in 2012 after I had my son. And it immediately stopped all bleeding the whole time?

... I was on it. It accidentally came out after 3 1/2 years and I got preg. I just had my daughter in july. I went back with the mirena, and I bled for 3 weeks straight. During the second week, it was so heavy I got worried and called the doc. And she said to give it one more week. So I did, and it stopped. Then maybe one or two weeks later, I started bleeding again. Like a period, which has now been going on for 13 days. (All of which never happened the first time I had the mirena) So should I be worried? Should I go see the doc about it? My body is reacting the complete opposite as it did when I had the mirena a year ago